Before beginning our research on radio waves, to us, radio waves were just waves going through the atmosphere, carrying sound from one place to another. Those were our ignorant days! We did not realize the complicated terms and theories involved. In the following report you will see how we advanced in our knowledge of radio waves, and we hope it will do the same for you. Radio waves are a combination of two kinds of electric vibrations. Audio frequency waves, which represent voice and other sounds and radio frequency waves, which carry audio waves after being combined with them. Two examples of broadcast waves are AM waves and FM waves.
AM which stands for amplitude modulation, is a broadcasting method in which the carrier waves (carry the sounds of a program) are changed to match changes in the audio frequency waves. These are electric waves that represent the sounds of a radio broadcast. FM stands for frequency modulation and these waves, that go skyward, are not reflected. Instead, they pass through the atmosphere and go into space.
AM signals, however, reflect off the atmosphere and travel back down to earth, causing broadcasts to be received at a much greater distance than FM signals. Since FM travels all the way to space and it does not bounce off the ground it does not create as much static as AM does. Radio waves, which travel at the speed of light, cannot be seen, heard, or felt in any way. When you listen to the radio, contrary to what some think, you a rehearing the receivers pick up the waves and turn them into sound. Three more types of radio waves are; ground waves, ionospheric waves and tropospheric waves. Ground waves travel from the antenna along the surface of the earth.
Ionospheric waves, otherwise known as sky waves, are made up of radio waves that come from a transmitting antenna and go into the sky. The ionosphere is the region of the rare field and ionized atmosphere around the earth, from 50 to 200 miles. Last but not least are the tropospheric waves. These waves are parts of the original wave which is reflected into the troposphere, an area of clouds and storms from 3 to 7 miles high. Radios change sound into electrical patterns with transmitters. In a radio transmitter, the circuit that generates the high frequency AC current that produces radio waves from an antenna, is called an oscillator.
Electrical patterns are then changed into broadcast waves of electromagnetic energy. The Ken elly-Heairside layer, found in a transmission of a radio is now well known. This keeps the energy spent by a shortwave transmitter from escaping into space. This is why we are able to receive shortwave from such a great distance. Sound is changed into radio waves at a radiobroadcast station.
The microphone, which is used, changes the sound into an electrical current. The transistors in an amplifier increase the strength of the current. Then, the current goes into the transmitter which is connected to an antenna. The antenna sends out the radio waves.
Although broadcast waves are almost constantly surrounding us, they can only be sensed by a similar antenna. When you are turning the dial on your radio to get a new station, you are actually picking up a new broadcast frequency. The frequency of a wave is the number of cycles that happen in one second. Hertz is a unit used to measure frequency. 1 Hertz is equal to 1 vibration per second. There is a way to figure out the speed at which a radio wave travels.
It is by multiplying the frequency of a wave by its wave length. The wave length is the distance between peaks. Diodes can detect radio waves. They were used in radio broadcasting, but transistors have taken their place. Radio waves are used in much more than just radios. They are also used in cordless telephones, television channels, and many appliances in the average home.
In conclusion, radio waves have become part of everyday life, and almost a necessity. Radio waves are just another example of our advancing technology on earth. As you have seen, radio waves are very complex. We hope our report has enabled you to further understand radio waves, it sure has for us!